1. Field of the Invention
The present invention relates to a spool lock member and a photo film cassette having the same. More particularly, the present invention relates to a spool lock member for a photo film cassette, capable of reliably locking a spool, and the photo film cassette having the same.
2. Description Related to the Prior Art
A photo film cassette of the IX240 type is characterized in that a leader of a photo film is advanced to the outside of the cassette shell. As disclosed in U.S. Pat. No. 5,317,355, the photo film cassette includes a structure for shielding ambient light, an indicator mechanism, a spool lock mechanism and the like.
The indicator mechanism indicates a status of the photo film in the outside of the photo film cassette among four statuses of being unexposed, partially exposed, exposed and developed. The indicator mechanism includes four windows shaped differently and an indicator plate portion. The windows are formed in one end wall of the photo film cassette, and have shapes of a circle, a letter D, a cross and a square. The indicator plate portion has a color different from the photo film cassette. A spool is provided with the indicator plate portion, and rotatable together. A camera or a video printer, which is for use with the photo film cassette, effects a control of rotationally stopping the spool in a suitable position. The spool is stopped in such a position that the indicator plate portion is positioned behind one of the windows associated with the particular present status of the photo film.
To shield ambient light, a cassette shutter is disposed in a photo film passageway in an openable manner. The cassette shutter rotates between closed and open positions, and when in the closed position, blocks ambient light through the photo film passageway, and when in the open position, allows the photo film to pass the photo film passageway. The camera has a drive shaft, which is engaged with the cassette shutter and rotates the same when the camera loaded with the photo film cassette.
The spool lock mechanism includes a spool lock member and a toothed wheel portion formed with the spool. The spool lock member includes first and second spring arms extending in a V-shape, and is shiftable between a locked position and an unlocked position, and when in the locked position, blocks rotation of the spool, and when in the unlocked position, allows the spool to rotate. The first arm has a shutter engaging end portion. When the cassette shutter is in the closed position, the shutter engaging end portion is pushed by a cam portion of the cassette shutter. When the cassette shutter is in the open position, the shutter engaging end portion is released from the cam portion of the cassette shutter. An end of the second arm has a positioning click claw. A middle portion of the second arm has a spool lock projection.
When the spool lock member is in the unlocked position, the positioning click claw becomes engaged with a claw receiving click projection formed on an inner surface of the photo film cassette to retain the spool lock member in the unlocked position. The spool lock projection, when the spool lock member is in the locked position, comes into a rotational orbit of the toothed wheel portion, and when the spool lock member is in the unlocked position, comes out of the rotational orbit of the toothed wheel portion.
In the first arm, the shutter engaging end portion is pushed by the cassette shutter when the cassette shutter is rotated to the closed position. The first arm is resiliently deformed toward the second arm. In the spool lock member, the first arm is deformed to shift the second arm in a direction away from the first arm. The positioning click claw is moved past the claw receiving click projection to shift the spool lock member to the locked position. Even when the spool lock member is shifted to the locked position, the shutter engaging end portion is still pushed by the cam portion of the cassette shutter. The second arm remains biased to press the spool lock projection to an interdental spaces between the toothed wheel portion. Thus, rotation of the spool is blocked firmly.
In the photo film cassette mentioned above, it is likely that the indicator plate portion indicates an erroneous status even while the spool lock member is in the locked position. This is because the stopped position of the spool is accidentally changed by application of rotational force to the spool upon shock, vibration or inadvertent manual touch. If the spool is rotated while locked, one of teeth of the toothed wheel portion pushes the spool lock projection to shift the second arm toward the first arm. The first arm does not move, as the shutter engaging end portion remains pushed by the cam portion of the cassette shutter. In contrast, the second arm is deformed resiliently as much as the space defined between it and the first arm. Thus, the tooth of the toothed wheel portion is moved past the spool lock projection.
In a process for mounting the spool lock member into the spool, an automatic assembling device is used. The use of the automatic assembling device requires automation of supply of the spool lock member. In a station upstream from the automatic assembling device, the spool lock member should be regularly oriented, and fed one by one.
An example of the supply device is a part feeder for feeding parts one after another in an regulated orientation by applying vibration to those collected irregularly. The part feeder includes a vibrating bucket into which a great number of parts are entered.
If a great number of spool lock members described above are entered in the vibrating bucket, it is likely that the spool lock members are entangled with one another in the vibrating bucket due to the V-shape with the first and second arms. There occurs failure in supply of the spool lock members one after another.
In view of the foregoing problems, an object of the present invention is to provide a spool lock member for a photo film cassette, which can be manufactured efficiently in an automated system, and the photo film cassette having the same.
Another object of the present invention is to provide a spool lock member for a photo film cassette, capable of locking a spool tightly and firmly, and the photo film cassette having the same.
In order to achieve the above and other objects and advantages of this invention, a spool lock member is incorporated in a photo film cassette, and prevents a spool from rotating when a rotatable cassette shutter for a photo film passageway is in a closed position. In the spool lock member, there is a base portion. A first arm extends from the base portion toward the cassette shutter, for shifting in a first direction in response to rotation of the cassette shutter toward the closed position. A second arm extends from the base portion toward the spool, for blocking rotation of the spool by shifting in the first direction with the first arm. The first and second arms have respectively first and second end portions opposite to the base portion, having a greater width or thickness than an interval between the first and second arms, and prevented from accidental entry between the first and second arms of another spool lock member before being assembled.
In a preferred embodiment, the photo film cassette is IX240 type.
The photo film cassette includes a toothed wheel portion formed with the spool. Furthermore, a spool lock projection is formed with the second arm, meshed with the toothed wheel portion upon shifting in the first direction, for blocking rotation thereof, the spool lock projection being pushed by and separated from the toothed wheel portion in a second direction opposite to the first direction upon application of rotating torque to the spool while the cassette shutter is in an open position. A regulator projection is formed with one of the first and second arms to project toward remainder thereof, for preventing the second arm from coming nearer to the first arm than a predetermined position, to keep the spool lock projection in mesh with the toothed wheel portion even upon application of high rotating torque to the spool while the cassette shutter is in the closed position.
The photo film cassette includes a cam portion, formed with the cassette shutter, having a diameter increasing with respect to an axial direction thereof, for pushing the first end portion in the first direction when the cassette shutter is rotated to the closed position.
The photo film cassette includes a roll chamber for containing a middle portion of the spool and a roll of photo film. A lock chamber is disposed beside the roll chamber, the spool and the cassette shutter extending into the lock chamber, the lock chamber containing the toothed wheel portion and the cam portion. The spool lock member is contained in the lock chamber.
The photo film cassette includes an advancing mechanism for advancing the photo film to an outside of the photo film passageway when the spool is rotated.
The regulator projection is formed with the second arm.
The photo film cassette includes a support portion, formed with an inside thereof, for supporting the base portion, to keep the first and second arms shiftable.
The second arm includes a first partial arm having the spool lock projection. A second partial arm extends from the first partial arm in a direction opposite to the base portion. A positioning claw is formed with an end of the second partial arm, for constituting the second end portion. The photo film cassette includes a claw receiving portion for retaining the positioning claw in a first retaining position when the second arm shifts in the first direction, to keep the spool lock projection in mesh with the toothed wheel portion, and for retaining the positioning claw in a second retaining position when the second arm shifts in the second direction, to keep the spool lock projection disengaged from the toothed wheel portion.